The Medicine Lodge Treaty is signed by southern Great Plains Indian leaders. The treaty requires Native American Plains tribes to relocate to a reservation in the western Indian Territory.

The Medicine Lodge Treaty is the overall name for three treaties signed near Medicine Lodge, Kansas, between the Federal government of the United States and southern Plains Indian tribes in October 1867, intended to bring peace to the area by relocating the Native Americans to reservations in Indian Territory and away from European-American settlement. The treaty was negotiated after investigation by the Indian Peace Commission, which in its final report in 1868 concluded that the wars had been preventable. They determined that the United States government and its representatives, including the United States Congress, had contributed to the warfare on the Great Plains by failing to fulfill their legal obligations and to treat the Native Americans with honesty.

Plains Indians or Indigenous peoples of the Great Plains and Canadian Prairies are the Native American tribes and First Nations peoples who have historically lived on the Interior Plains of North America. While hunting-farming cultures have lived on the Great Plains for centuries prior to European contact, the region is known for the horse cultures that flourished from the 17th century through the late 19th century. Their historic nomadism and armed resistance to domination by the government and military forces of Canada and the United States have made the Plains Indian culture groups an archetype in literature and art for Native Americans everywhere.

Indian Territory and the Indian Territories are terms that generally described an evolving land area set aside by the United States government for the relocation of Native Americans who held original Indian title to their land as an independent nation. The concept of an Indian territory was an outcome of the U.S. federal government's 18th- and 19th-century policy of Indian removal. After the American Civil War (1861–1865), the policy of the U.S. government was one of assimilation.